> The patch adds a protocol extension called _pq_.wait_for_lsn as well
> as a libpq connection option wait_for_lsn to activate the same. (Use
> e.g., psql -d 'wait_for_lsn=1'.)
>
> With this protocol extension, two things are changed:
>
> - The ReadyForQuery message sends back the current LSN.
If other protocol extension X tries to add something to the
ReadyForQuery message too, what would happen?
Currently ReadyForQuery message is like this:
Byte1('Z')
Int32
Byte1
With the wait_for_lsn extension, It becomes:
Byte1('Z')
Int32
Byte1
String
Suppose the X extension wants to extend like this:
Byte1('Z')
Int32
Byte1
Int32
It seems impossible to coexist both.
Does this mean once the wait_for_lsn extension is brought into the
frontend/backend protocol specification, no other extensions that touch
ReadyForQuery cannot be defined?
Best reagards,
--
Tatsuo Ishii
SRA OSS K.K.
English: http://www.sraoss.co.jp/index_en/
Japanese:http://www.sraoss.co.jp
